WO2012033045A1 - Nonaqueous electrolyte battery - Google Patents

Nonaqueous electrolyte battery Download PDF

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Publication number
WO2012033045A1
WO2012033045A1 PCT/JP2011/070144 JP2011070144W WO2012033045A1 WO 2012033045 A1 WO2012033045 A1 WO 2012033045A1 JP 2011070144 W JP2011070144 W JP 2011070144W WO 2012033045 A1 WO2012033045 A1 WO 2012033045A1
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WIPO (PCT)
Prior art keywords
flame retardant
positive electrode
negative electrode
battery
electrode plate
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PCT/JP2011/070144
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French (fr)
Japanese (ja)
Inventor
辻川　知伸
荒川　正泰
傳馬　寛一
林　晃司
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新神戸電機株式会社
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Application filed by 新神戸電機株式会社 filed Critical 新神戸電機株式会社
Priority to EP11823520.9A priority Critical patent/EP2615667A4/en
Priority to KR1020137005734A priority patent/KR20140012020A/en
Priority to CN201180042827.3A priority patent/CN103081182B/en
Priority to US13/820,813 priority patent/US20130216908A1/en
Publication of WO2012033045A1 publication Critical patent/WO2012033045A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/431—Inorganic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/46—Separators, membranes or diaphragms characterised by their combination with electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a non-aqueous electrolyte battery, and in particular, a positive electrode plate in which a positive electrode mixture layer containing an active material is formed on a current collector, and a negative electrode in which a negative electrode mixture layer containing an active material is formed on a current collector
  • the present invention relates to a non-aqueous electrolyte battery in which a plate is disposed via a porous separator.
  • Alkaline storage batteries, lead storage batteries, and the like are known as secondary batteries in which the electrolytic solution is an aqueous solution system.
  • non-aqueous electrolyte batteries typified by lithium secondary batteries, which are small, light, and have high energy density, are in widespread use.
  • the electrolyte used for the nonaqueous electrolyte battery contains an organic solvent such as dimethyl ether. Due to the flammability of organic solvents, when battery temperature rises during battery abnormalities such as overcharge or internal short circuit or when dropped in fire, battery behavior is severe due to combustion of battery components and thermal decomposition of active materials. There is a risk.
  • the techniques disclosed in Japanese Patent Application Laid-Open Nos. 4-184870 and 2006-127839 are techniques for incombusting the non-aqueous electrolyte containing a flame retardant and the battery constituent material itself of the separator. It is difficult to make incombustible.
  • this technology is applied to a lithium secondary battery, the lithium secondary battery generates a large amount of heat due to the thermal decomposition reaction of the active material, and therefore a large amount of flame retardant is required to suppress the temperature rise.
  • a separator containing a large amount of a flame retardant may cause a problem that it is difficult to maintain the strength originally required for the separator.
  • an object of the present invention is to provide a non-aqueous electrolyte battery capable of ensuring safety when a battery is abnormal and suppressing deterioration of charge / discharge characteristics when the battery is used.
  • the present invention provides a positive electrode plate in which a positive electrode mixture layer containing an active material is formed on a current collector, and a negative electrode plate in which a negative electrode mixture layer containing an active material is formed on a current collector.
  • a flame retardant layer containing a flame retardant is disposed on one or both surfaces of the positive electrode plate, the negative electrode plate, and the separator.
  • a carbon material having electronic conductivity and having a mass ratio with respect to the flame retardant of 25% or less is included in the flame retardant layer.
  • the carbon material contained in the flame retardant layer preferably has a mass ratio of 1% or more to the flame retardant.
  • the carbon material contained in the flame retardant layer preferably has a mass ratio with respect to the flame retardant of 2 to 20%.
  • the flame retardant layer is disposed on one or both sides of the positive electrode plate or the negative electrode plate, and the thickness of the flame retardant layer is 20% or less with respect to the thickness of the positive electrode mixture layer or the negative electrode mixture layer. It is good.
  • the carbon material contained in the flame retardant layer can be one or a combination of at least two selected from graphite, carbon black, acetylene black, carbon nanotube, and glassy carbon.
  • the graphite may be one or a combination of at least two selected from scale-like graphite, artificial graphite, and earth-like graphite.
  • a flame retardant layer containing a flame retardant is disposed on at least one of the positive electrode plate, the negative electrode plate, and the separator. Since the flame retardant suppresses the combustion of the battery constituent material, the battery behavior can be moderated and safety can be ensured, and the carbon material has electronic conductivity and a mass ratio to the flame retardant of 25% or less. Is contained in the flame retardant layer, it is possible to obtain an effect that deterioration of charge / discharge characteristics can be suppressed.
  • a cylindrical lithium ion secondary battery (non-aqueous electrolyte battery) 20 has a nickel-plated steel bottomed cylindrical battery container 7. .
  • the battery container 7 accommodates an electrode group 6 in which strip-like positive and negative electrode plates are wound in a spiral shape through a separator.
  • an annular conductor negative electrode current collecting ring 5 for collecting the electric potential from the negative electrode plate is disposed below the electrode group 6.
  • the outer peripheral surface of the lower end portion of the shaft core 1 is fixed to the inner peripheral surface of the negative electrode current collecting ring 5.
  • the end of the negative electrode lead piece 3 led out from the negative electrode plate is joined to the outer peripheral edge of the negative electrode current collecting ring 5 by ultrasonic welding.
  • the lower part of the negative electrode current collection ring 5 is connected to the inner bottom part of the battery container 7 through a conductor lead.
  • the dimensions of the battery container 7 are set to an outer diameter of 40 mm and an inner diameter of 39 mm.
  • the battery lid 11 is caulked and fixed to the upper part of the battery container 7 via an insulating and heat resistant EPDM resin gasket 10. For this reason, the inside of the lithium ion secondary battery 20 is sealed.
  • a non-aqueous electrolyte is injected into the battery container 7.
  • the non-aqueous electrolyte includes lithium hexafluorophosphate (LiPF 6) as a lithium salt in a mixed solvent of ethylene carbonate (EC), dimethyl carbonate (DMC), and diethyl carbonate (DEC) in a volume ratio of 1: 1: 1. 1) / mol dissolved.
  • the lithium ion secondary battery 20 is given a battery function by performing initial charging at a predetermined voltage and current.
  • the positive electrode plate and the negative electrode plate are wound around the shaft core 1 through a porous polyethylene separator W5 through which lithium ions can pass so that the two electrode plates do not directly contact each other.
  • the thickness of the separator W5 is set to 30 ⁇ m.
  • the positive electrode lead piece 2 and the negative electrode lead piece 3 are arranged on both end surfaces of the electrode group 6 opposite to each other.
  • the diameter of the electrode group 6 is set to 38 ⁇ 0.5 mm by adjusting the lengths of the positive electrode plate, the negative electrode plate, and the separator W5. Insulation coating is applied to the entire circumference of the collar peripheral surface of the electrode group 6 and the positive electrode current collecting ring 4 in order to prevent electrical contact between the electrode group 6 and the battery container 7.
  • an adhesive tape in which a hexamethacrylate adhesive is applied to one side of a polyimide base material is used.
  • the pressure-sensitive adhesive tape is wound one or more times from the collar surface to the outer circumferential surface of the electrode group 6. The number of turns is adjusted so that the maximum diameter portion of the electrode group 6 becomes an insulating coating existing portion, and the maximum diameter is set slightly smaller than the inner diameter of the battery container 7.
  • the positive electrode plate constituting the electrode group 6 has an aluminum foil (current collector) W1 as a positive electrode current collector.
  • the thickness of the aluminum foil W1 is set to 20 ⁇ m.
  • the positive electrode mixture is applied substantially uniformly and uniformly to form a positive electrode mixture layer W2.
  • the positive electrode mixture contains a lithium transition metal double oxide as a positive electrode active material.
  • the thickness of the formed positive electrode mixture layer W2 is substantially uniform, and the positive electrode mixture is substantially uniformly dispersed in the positive electrode mixture layer W2.
  • the lithium transition metal double oxide for example, manganese nickel cobalt lithium double acid powder having a layered crystal structure or lithium manganate powder having a spinel crystal structure can be used.
  • Examples of the positive electrode mixture include 85 wt% (mass%) of lithium transition metal double oxide, 8 wt% of scaly graphite and 2 wt% of acetylene black as a conductive material, and polyfluoride as a binder (binder). 5 wt% of vinylidene chloride (hereinafter abbreviated as PVdF) is blended.
  • PVdF vinylidene chloride
  • NMP dispersion solvent N-methyl-2-pyrrolidone
  • An uncoated portion of a positive electrode mixture having a width of 30 mm is formed on the side edge on one side in the longitudinal direction of the aluminum foil W1.
  • the uncoated part is cut out in a comb shape, and the positive electrode lead piece 2 is formed in the notch remaining part.
  • the interval between the adjacent positive electrode lead pieces 2 is set to 20 mm, and the width of the positive electrode lead piece 2 is set to 5 mm.
  • the positive electrode plate is pressed after drying and cut into a width of 80 mm.
  • a flame retardant layer W6 containing a flame retardant is formed on the surface of the positive electrode mixture layer W2, that is, on both surfaces of the positive electrode plate.
  • the thickness of the flame retardant layer W6 is set to 20% or less with respect to the thickness of the positive electrode mixture layer W2.
  • the flame retardant layer W6 contains a carbon material having electronic conductivity, and is made porous by blending a pore forming agent (pore forming agent) so as to have lithium ion permeability.
  • a pore forming agent pore forming agent
  • the flame retardant a phosphazene compound having phosphorus and nitrogen as a basic skeleton is used.
  • the blending ratio of the flame retardant is set to 1 wt% or more with respect to the positive electrode mixture.
  • the phosphazene compound is a cyclic compound represented by the general formula (NPR 2 ) 3 or (NPR 2 ) 4 .
  • R in the general formula represents a halogen element such as fluorine or chlorine or a monovalent substituent.
  • alkoxy groups such as methoxy group and ethoxy group, aryloxy groups such as phenoxy group and methylphenoxy group, alkyl groups such as methyl group and ethyl group, aryl groups such as phenyl group and tolyl group
  • alkoxy groups such as methoxy group and ethoxy group
  • aryloxy groups such as phenoxy group and methylphenoxy group
  • alkyl groups such as methyl group and ethyl group
  • aryl groups such as phenyl group and tolyl group
  • Examples thereof include an amino group containing a substituted amino group such as a methylamino group, an alkylthio group such as a methylthio group and an ethylthio group, and an arylthio group such as a phenylthio group.
  • a solid phosphazene compound is used in a temperature environment of 80 ° C. or lower. Further, these phosphazene compounds are
  • the negative electrode plate has a rolled copper foil (current collector) W3 as a negative electrode current collector.
  • the thickness of the rolled copper foil W3 is set to 10 ⁇ m.
  • the negative electrode mixture is applied substantially uniformly and uniformly in the same manner as the positive electrode plate to form a negative electrode mixture layer W4.
  • the negative electrode mixture contains a carbon material capable of occluding and releasing lithium ions as a negative electrode active material.
  • amorphous carbon powder is used for the carbon material of the negative electrode active material.
  • 10 wt% of PVdF is blended as a binder with respect to 90 wt% of the amorphous carbon powder.
  • NMP as a dispersion solvent When applying the negative electrode mixture to the rolled copper foil W3, NMP as a dispersion solvent is used. An uncoated portion of a negative electrode mixture having a width of 30 mm is formed on the side edge on one side in the longitudinal direction of the rolled copper foil W3, and a negative electrode lead piece 3 is formed. The interval between the adjacent negative electrode lead pieces 3 is set to 20 mm, and the width of the negative electrode lead piece 3 is set to 5 mm. The negative electrode plate is pressed after drying and cut into a width of 86 mm. The length of the negative electrode plate is such that when the positive electrode plate and the negative electrode plate are wound, the positive electrode plate does not protrude from the negative electrode plate in the winding direction at the innermost winding and outermost winding.
  • the width of the negative electrode mixture layer W4 (mixture application portion) is such that the positive electrode mixture layer W2 does not protrude from the negative electrode mixture layer W4 in the direction perpendicular to the winding direction. 6 mm longer.
  • Example 1 In Example 1, a phosphazene compound as a flame retardant (trade name Phoslite (registered trademark) manufactured by Bridgestone Corporation, solid, decomposition temperature 250 ° C. or higher) and PVdF were dissolved in an NMP solution containing aluminum oxide and a carbon material. Acetylene black (Denka Black HS100, manufactured by Denki Kagaku Kogyo Co., Ltd.) was dispersed to prepare a dispersion solution. At this time, as shown in Table 1 below, the mass ratio of the carbon material to the flame retardant was adjusted to 1%. This dispersion solution was applied to the surface of the positive electrode mixture layer W2, and the application amount of the dispersion solution was adjusted to adjust the blending ratio of the flame retardant to the positive electrode mixture to 1 wt%.
  • a phosphazene compound as a flame retardant trade name Phoslite (registered trademark) manufactured by Bridgestone Corporation, solid, decomposition temperature 250 ° C. or higher
  • PVdF dissolved
  • Example 2 to Example 7 As shown in Table 1, Examples 2 to 7 were the same as Example 1 except that the mass ratio of the carbon material to the flame retardant was changed in the range of 2 to 25%. That is, the mass ratio of the carbon material is 2% in Example 2, 5% in Example 3, 10% in Example 4, 15% in Example 5, 20% in Example 6, and 25% in Example 7. , Respectively.
  • Comparative Example 1 was the same as Example 1 except that the flame retardant layer did not contain a carbon material. That is, the lithium ion secondary battery of Comparative Example 1 is a battery in which the mass ratio of the carbon material to the flame retardant is 0%.
  • Comparative Examples 2 to 9 were the same as Example 1 except that the mass ratio of the carbon material to the flame retardant was changed in the range of 30 to 100%. That is, the mass ratio of the carbon material is 30% in Comparative Example 2, 40% in Comparative Example 3, 50% in Comparative Example 4, 60% in Comparative Example 5, 70% in Comparative Example 6, and 80% in Comparative Example 7. Comparative Example 8 was adjusted to 90%, and Comparative Example 9 was adjusted to 100%.
  • Test 1 The following measurements and tests were performed on the lithium ion secondary batteries of Examples and Comparative Examples. The discharge capacity was measured at an ambient temperature of 25 ° C. and 700 mA (1C), and the discharge capacity at 1C of the lithium ion secondary battery of Comparative Example 1 in which the mass ratio of the carbon material to the flame retardant was 0% was assumed to be 100%. The discharge capacity ratio was determined for each of the lithium ion secondary batteries of Examples and Comparative Examples.

Abstract

Provided is a nonaqueous electrolyte battery capable of ensuring safety during battery malfunction and inhibiting the depletion of charge-discharge characteristics during battery usage. In the present invention, a lithium ion secondary battery (20) comprises an electrode group (6) contained in a battery container (7). The electrode group (6) comprises positive electrode plates and negative electrode plates coiled with separators (W5) in between. The positive electrode plates are provided with an aluminum foil (W1) which is a positive electrode current collector. A positive electrode compound layer (W2) containing a positive electrode active material is formed on both sides of the aluminum foil (W1). A flame retardant layer (W6) containing a flame retardant is formed on both sides of the positive electrode compound layer (W2). The flame retardant layer (W6) is provided with electron conductivity, and contains carbon material which is 25% or less in mass compared with the flame retardant. The negative electrode plate is provided with a rolled copper foil (W3) which is a negative electrode current collector. A negative electrode compound layer (W4) containing a negative electrode active material is formed on both sides of the rolled copper foil (W3). As such, electron conductivity is ensured during battery use, and the retardant agent disintegrates during battery malfunction.

Description

非水電解液電池Non-aqueous electrolyte battery
　本発明は非水電解液電池に係り、特に、活物質を含む正極合剤層が集電体に形成された正極板と、活物質を含む負極合剤層が集電体に形成された負極板とが多孔質セパレータを介して配置された非水電解液電池に関する。 The present invention relates to a non-aqueous electrolyte battery, and in particular, a positive electrode plate in which a positive electrode mixture layer containing an active material is formed on a current collector, and a negative electrode in which a negative electrode mixture layer containing an active material is formed on a current collector The present invention relates to a non-aqueous electrolyte battery in which a plate is disposed via a porous separator.
　電解液が水溶液系である二次電池としては、アルカリ蓄電池や鉛蓄電池等が知られている。これらの水溶液系二次電池に代わり、小型、軽量かつ高エネルギー密度であり、リチウム二次電池に代表される非水電解液電池が普及している。非水電解液電池に用いられる電解液には、ジメチルエーテル等の有機溶媒が含まれている。有機溶媒が可燃性を有するため、過充電や内部短絡等の電池異常時や火中投下時に電池温度が上昇した場合には、電池構成材料の燃焼や活物質の熱分解反応により電池挙動が激しくなるおそれがある。 Alkaline storage batteries, lead storage batteries, and the like are known as secondary batteries in which the electrolytic solution is an aqueous solution system. Instead of these aqueous secondary batteries, non-aqueous electrolyte batteries typified by lithium secondary batteries, which are small, light, and have high energy density, are in widespread use. The electrolyte used for the nonaqueous electrolyte battery contains an organic solvent such as dimethyl ether. Due to the flammability of organic solvents, when battery temperature rises during battery abnormalities such as overcharge or internal short circuit or when dropped in fire, battery behavior is severe due to combustion of battery components and thermal decomposition of active materials. There is a risk.
　このような事態を回避し電池の安全性を確保するために種々の安全化技術が提案されている。例えば、非水電解液に難燃化剤（不燃性付与物質）を溶解させて非水電解液を不燃化する技術（日本国特開平４－１８４８７０号公報参照）、セパレータに難燃化剤を分散させてセパレータを不燃化する技術（日本国特開２００６－１２７８３９号公報参照）が開示されている。 In order to avoid such a situation and ensure the safety of the battery, various safety technologies have been proposed. For example, a technology for making a non-aqueous electrolyte non-flammable by dissolving a flame retardant (non-flammability imparting substance) in a non-aqueous electrolyte (see Japanese Patent Laid-Open No. 4-184870), and a flame retardant for a separator A technique for making the separator non-flammable by dispersing (see Japanese Patent Application Laid-Open No. 2006-127839) is disclosed.
　しかしながら、特開平４－１８４８７０号公報、特開２００６－１２７８３９号公報の技術では、難燃化剤を含有させた非水電解液やセパレータの電池構成材料自体を不燃化する技術であり、電池そのものを不燃化することは難しい。例えば、特開２００６－１２７８３９号公報の技術において、セパレータ中に含有させる難燃化剤の量によりセパレータ自身に不燃性を付与することが可能となる。この技術をリチウム二次電池に適用した場合は、リチウム二次電池では活物質の熱分解反応による発熱が大きくなるため、温度上昇を抑制するには多量の難燃化剤が必要となる。また、難燃化剤を多く含ませたセパレータでは、セパレータとして本来求められる強度を保つことが難しくなる、といった問題も生じる可能性がある。 However, the techniques disclosed in Japanese Patent Application Laid-Open Nos. 4-184870 and 2006-127839 are techniques for incombusting the non-aqueous electrolyte containing a flame retardant and the battery constituent material itself of the separator. It is difficult to make incombustible. For example, in the technique disclosed in Japanese Patent Application Laid-Open No. 2006-127839, it is possible to impart nonflammability to the separator itself by the amount of the flame retardant contained in the separator. When this technology is applied to a lithium secondary battery, the lithium secondary battery generates a large amount of heat due to the thermal decomposition reaction of the active material, and therefore a large amount of flame retardant is required to suppress the temperature rise. Further, a separator containing a large amount of a flame retardant may cause a problem that it is difficult to maintain the strength originally required for the separator.
　本発明は上記事案に鑑み、電池異常時の安全性を確保し電池使用時の充放電特性の低下を抑制することができる非水電解液電池を提供することを課題とする。 In view of the above circumstances, an object of the present invention is to provide a non-aqueous electrolyte battery capable of ensuring safety when a battery is abnormal and suppressing deterioration of charge / discharge characteristics when the battery is used.
　上記課題を解決するために、本発明は、活物質を含む正極合剤層が集電体に形成された正極板と、活物質を含む負極合剤層が集電体に形成された負極板とが多孔質セパレータを介して配置された非水電解液電池において、前記正極板、負極板およびセパレータの少なくとも１種の片面または両面に、難燃化剤を含む難燃化剤層が配され、電子伝導性を有し、該難燃化剤に対する質量比が２５％以下の炭素材料が前記難燃化剤層に含まれたことを特徴とする。 In order to solve the above problems, the present invention provides a positive electrode plate in which a positive electrode mixture layer containing an active material is formed on a current collector, and a negative electrode plate in which a negative electrode mixture layer containing an active material is formed on a current collector. In a non-aqueous electrolyte battery in which a porous separator is disposed, a flame retardant layer containing a flame retardant is disposed on one or both surfaces of the positive electrode plate, the negative electrode plate, and the separator. A carbon material having electronic conductivity and having a mass ratio with respect to the flame retardant of 25% or less is included in the flame retardant layer.
　本発明において、難燃化剤層に含まれる炭素材料は、難燃化剤に対する質量比が１％以上であることが好ましい。また、難燃化剤層に含まれる炭素材料は、難燃化剤に対する質量比が２～２０％の範囲であることがより好ましい。難燃化剤層は、正極板ないし負極板の片面または両面に配されており、難燃化剤層の厚さを、正極合剤層または負極合剤層の厚さに対して２０％以下としてもよい。難燃化剤層に含まれる炭素材料は、グラファイト、カーボンブラック、アセチレンブラック、カーボンナノチューブ、ガラス状炭素から選択される１種または少なくとも２種の組み合わせとすることができる。グラファイトは、鱗片状グラファイト、人造グラファイト、土状グラファイトから選択される１種または少なくとも２種の組み合わせとしてもよい。 In the present invention, the carbon material contained in the flame retardant layer preferably has a mass ratio of 1% or more to the flame retardant. The carbon material contained in the flame retardant layer preferably has a mass ratio with respect to the flame retardant of 2 to 20%. The flame retardant layer is disposed on one or both sides of the positive electrode plate or the negative electrode plate, and the thickness of the flame retardant layer is 20% or less with respect to the thickness of the positive electrode mixture layer or the negative electrode mixture layer. It is good. The carbon material contained in the flame retardant layer can be one or a combination of at least two selected from graphite, carbon black, acetylene black, carbon nanotube, and glassy carbon. The graphite may be one or a combination of at least two selected from scale-like graphite, artificial graphite, and earth-like graphite.
　本発明によれば、正極板、負極板およびセパレータの少なくとも１種の片面または両面に、難燃化剤を含む難燃化剤層が配されたことで、電池異常で温度上昇したときに難燃化剤が電池構成材料の燃焼を抑制するため、電池挙動を穏やかにし安全性を確保することができると共に、電子伝導性を有し、難燃化剤に対する質量比が２５％以下の炭素材料が難燃化剤層に含まれるため、充放電特性の低下を抑制することができる、という効果を得ることができる。 According to the present invention, a flame retardant layer containing a flame retardant is disposed on at least one of the positive electrode plate, the negative electrode plate, and the separator. Since the flame retardant suppresses the combustion of the battery constituent material, the battery behavior can be moderated and safety can be ensured, and the carbon material has electronic conductivity and a mass ratio to the flame retardant of 25% or less. Is contained in the flame retardant layer, it is possible to obtain an effect that deterioration of charge / discharge characteristics can be suppressed.
本発明を適用可能な実施形態の円柱型リチウムイオン二次電池の断面図である。It is sectional drawing of the cylindrical lithium ion secondary battery of embodiment which can apply this invention. 難燃化剤に対する炭素材料の質量比を変化させて作製した実施例および比較例のリチウムイオン電池について１Ｃ放電容量比を示すグラフである。It is a graph which shows 1C discharge capacity ratio about the lithium ion battery of the Example produced by changing the mass ratio of the carbon material with respect to a flame retardant, and a comparative example.
　以下、図面を参照して、本発明をハイブリッド自動車に搭載される円柱型リチウムイオン二次電池に適用した実施の形態について説明する。 Hereinafter, an embodiment in which the present invention is applied to a cylindrical lithium ion secondary battery mounted in a hybrid vehicle will be described with reference to the drawings.
　図１に示すように、本実施形態の円柱型リチウムイオン二次電池（非水電解液電池）２０は、ニッケルメッキが施されたスチール製で有底円筒状の電池容器７を有している。電池容器７には、帯状の正負極板がセパレータを介して断面渦巻状に捲回された電極群６が収容されている。 As shown in FIG. 1, a cylindrical lithium ion secondary battery (non-aqueous electrolyte battery) 20 according to this embodiment has a nickel-plated steel bottomed cylindrical battery container 7. . The battery container 7 accommodates an electrode group 6 in which strip-like positive and negative electrode plates are wound in a spiral shape through a separator.
　電極群６の捲回中心には、ポリプロピレン樹脂製で中空円筒状の軸芯１が使用されている。電極群６の上側には、軸芯１のほぼ延長線上に正極板からの電位を集電するための円環状導体の正極集電リング４が配置されている。正極集電リング４は、軸芯１の上端部に固定されている。正極集電リング４の周囲から一体に張り出している鍔部周縁には、正極板から導出された正極リード片２の端部が超音波溶接で接合されている。正極集電リング４の上方には、安全弁を内蔵し正極外部端子となる円盤状の電池蓋１１が配置されている。正極集電リング４の上部は、導体リードを介して電池蓋１１に接続されている。 A hollow cylindrical shaft core 1 made of polypropylene resin is used at the winding center of the electrode group 6. On the upper side of the electrode group 6, a positive electrode current collecting ring 4 of an annular conductor for collecting the electric potential from the positive electrode plate is disposed substantially on the extension line of the shaft core 1. The positive electrode current collecting ring 4 is fixed to the upper end portion of the shaft core 1. The edge part of the positive electrode lead piece 2 led out from the positive electrode plate is joined by ultrasonic welding to the peripheral edge of the flange part integrally protruding from the periphery of the positive electrode current collecting ring 4. Above the positive electrode current collecting ring 4, a disc-shaped battery lid 11 is provided that incorporates a safety valve and serves as a positive electrode external terminal. The upper part of the positive electrode current collecting ring 4 is connected to the battery lid 11 via a conductor lead.
　一方、電極群６の下側には負極板からの電位を集電するための円環状導体の負極集電リング５が配置されている。負極集電リング５の内周面には軸芯１の下端部外周面が固定されている。負極集電リング５の外周縁には、負極板から導出された負極リード片３の端部が超音波溶接で接合されている。負極集電リング５の下部は、導体リードを介して電池容器７の内底部に接続されている。電池容器７の寸法は、本例では、外径４０ｍｍ、内径３９ｍｍに設定されている。 On the other hand, an annular conductor negative electrode current collecting ring 5 for collecting the electric potential from the negative electrode plate is disposed below the electrode group 6. The outer peripheral surface of the lower end portion of the shaft core 1 is fixed to the inner peripheral surface of the negative electrode current collecting ring 5. The end of the negative electrode lead piece 3 led out from the negative electrode plate is joined to the outer peripheral edge of the negative electrode current collecting ring 5 by ultrasonic welding. The lower part of the negative electrode current collection ring 5 is connected to the inner bottom part of the battery container 7 through a conductor lead. In this example, the dimensions of the battery container 7 are set to an outer diameter of 40 mm and an inner diameter of 39 mm.
　電池蓋１１は、絶縁性および耐熱性のＥＰＤＭ樹脂製ガスケット１０を介して電池容器７の上部にカシメ固定されている。このため、リチウムイオン二次電池２０の内部は密封されている。また、電池容器７内には、非水電解液が注液されている。非水電解液には、エチレンカーボネート（ＥＣ）とジメチルカーボネート（ＤＭＣ）とジエチルカーボネート（ＤＥＣ）との体積比１：１：１の混合溶媒中にリチウム塩として６フッ化リン酸リチウム（ＬｉＰＦ６）を１モル／リットル溶解したものが用いられている。なお、リチウムイオン二次電池２０は、所定電圧および電流で初充電を行うことで、電池機能が付与される。 The battery lid 11 is caulked and fixed to the upper part of the battery container 7 via an insulating and heat resistant EPDM resin gasket 10. For this reason, the inside of the lithium ion secondary battery 20 is sealed. In addition, a non-aqueous electrolyte is injected into the battery container 7. The non-aqueous electrolyte includes lithium hexafluorophosphate (LiPF 6) as a lithium salt in a mixed solvent of ethylene carbonate (EC), dimethyl carbonate (DMC), and diethyl carbonate (DEC) in a volume ratio of 1: 1: 1. 1) / mol dissolved. The lithium ion secondary battery 20 is given a battery function by performing initial charging at a predetermined voltage and current.
　電極群６は、正極板と負極板とが、これら両極板が直接接触しないように、リチウムイオンが通過可能な多孔質ポリエチレン製セパレータＷ５を介し、軸芯１の周囲に捲回されている。セパレータＷ５の厚さは、本例では、３０μｍに設定されている。正極リード片２と負極リード片３とが、それぞれ電極群６の互いに反対側の両端面に配置されている。電極群６の直径は、本例では、正極板、負極板、セパレータＷ５の長さを調整することで、３８±０．５ｍｍに設定されている。電極群６および正極集電リング４の鍔部周面全周には、電極群６と電池容器７との電気的接触を防止するために絶縁被覆が施されている。絶縁被覆には、ポリイミド製の基材の片面にヘキサメタアクリレートの粘着剤が塗布された粘着テープが用いられている。粘着テープは鍔部周面から電極群６の外周面に亘って一重以上巻かれている。電極群６の最大径部が絶縁被覆存在部となるように巻き数が調整され、該最大径が電池容器７の内径より僅かに小さく設定されている。 In the electrode group 6, the positive electrode plate and the negative electrode plate are wound around the shaft core 1 through a porous polyethylene separator W5 through which lithium ions can pass so that the two electrode plates do not directly contact each other. In this example, the thickness of the separator W5 is set to 30 μm. The positive electrode lead piece 2 and the negative electrode lead piece 3 are arranged on both end surfaces of the electrode group 6 opposite to each other. In this example, the diameter of the electrode group 6 is set to 38 ± 0.5 mm by adjusting the lengths of the positive electrode plate, the negative electrode plate, and the separator W5. Insulation coating is applied to the entire circumference of the collar peripheral surface of the electrode group 6 and the positive electrode current collecting ring 4 in order to prevent electrical contact between the electrode group 6 and the battery container 7. For the insulation coating, an adhesive tape in which a hexamethacrylate adhesive is applied to one side of a polyimide base material is used. The pressure-sensitive adhesive tape is wound one or more times from the collar surface to the outer circumferential surface of the electrode group 6. The number of turns is adjusted so that the maximum diameter portion of the electrode group 6 becomes an insulating coating existing portion, and the maximum diameter is set slightly smaller than the inner diameter of the battery container 7.
　電極群６を構成する正極板は、正極集電体としてアルミニウム箔（集電体）Ｗ１を有している。アルミニウム箔Ｗ１の厚さは、本例では、２０μｍに設定されている。アルミニウム箔Ｗ１の両面には、正極合剤が実質的に均等かつ均質に塗着され正極合剤層Ｗ２が形成されている。正極合剤には、正極活物質としてリチウム遷移金属複酸化物が含まれている。形成された正極合剤層Ｗ２の厚さがほぼ一様であり、かつ、正極合剤層Ｗ２内では正極合剤がほぼ一様に分散されている。リチウム遷移金属複酸化物には、例えば、層状結晶構造を有するマンガンニッケルコバルト複酸リチウム粉末やスピネル結晶構造を有するマンガン酸リチウム粉末を用いることができる。正極合剤には、例えば、リチウム遷移金属複酸化物の８５ｗｔ％（質量％）に対して、導電材として鱗片状グラファイトの８ｗｔ％およびアセチレンブラックの２ｗｔ％と、バインダ（結着材）としてポリフッ化ビニリデン（以下、ＰＶｄＦと略記する。）の５ｗｔ％とが配合されている。アルミニウム箔Ｗ１に正極合剤を塗着するときには、分散溶媒のＮ－メチル－２－ピロリドン（以下、ＮＭＰと略記する。）が用いられる。アルミニウム箔Ｗ１の長寸方向一側の側縁には、幅３０ｍｍの正極合剤の未塗着部が形成されている。未塗着部は櫛状に切り欠かれており、切り欠き残部で正極リード片２が形成されている。隣り合う正極リード片２の間隔が２０ｍｍ、正極リード片２の幅が５ｍｍに設定されている。正極板は、乾燥後プレス加工され、幅８０ｍｍに裁断されている。 The positive electrode plate constituting the electrode group 6 has an aluminum foil (current collector) W1 as a positive electrode current collector. In this example, the thickness of the aluminum foil W1 is set to 20 μm. On both surfaces of the aluminum foil W1, the positive electrode mixture is applied substantially uniformly and uniformly to form a positive electrode mixture layer W2. The positive electrode mixture contains a lithium transition metal double oxide as a positive electrode active material. The thickness of the formed positive electrode mixture layer W2 is substantially uniform, and the positive electrode mixture is substantially uniformly dispersed in the positive electrode mixture layer W2. As the lithium transition metal double oxide, for example, manganese nickel cobalt lithium double acid powder having a layered crystal structure or lithium manganate powder having a spinel crystal structure can be used. Examples of the positive electrode mixture include 85 wt% (mass%) of lithium transition metal double oxide, 8 wt% of scaly graphite and 2 wt% of acetylene black as a conductive material, and polyfluoride as a binder (binder). 5 wt% of vinylidene chloride (hereinafter abbreviated as PVdF) is blended. When the positive electrode mixture is applied to the aluminum foil W1, a dispersion solvent N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) is used. An uncoated portion of a positive electrode mixture having a width of 30 mm is formed on the side edge on one side in the longitudinal direction of the aluminum foil W1. The uncoated part is cut out in a comb shape, and the positive electrode lead piece 2 is formed in the notch remaining part. The interval between the adjacent positive electrode lead pieces 2 is set to 20 mm, and the width of the positive electrode lead piece 2 is set to 5 mm. The positive electrode plate is pressed after drying and cut into a width of 80 mm.
　また、正極合剤層Ｗ２の表面、すなわち、正極板の両面には、難燃化剤を含む難燃化剤層Ｗ６が形成されている。難燃化剤層Ｗ６の厚さは、正極合剤層Ｗ２の厚さに対して、２０％以下に設定されている。難燃化剤層Ｗ６は、電子伝導性を有する炭素材料が含有されており、リチウムイオン透過性を有するように、造孔剤（孔形成剤）を配合することで多孔化されている。難燃化剤には、リンおよび窒素を基本骨格とするホスファゼン化合物が用いられている。難燃化剤の配合割合は、本例では、正極合剤に対して１ｗｔ％以上に設定されている。難燃化剤層Ｗ６に含有された炭素材料にはアセチレンブラックが用いられている。炭素材料の難燃化剤に対する質量比は、１～２５％の範囲に設定されている。また、造孔剤には酸化アルミニウムが用いられている。酸化アルミニウムの配合割合は、難燃化剤層Ｗ６に形成する多孔の割合に合わせて調整することができる。この難燃化剤層Ｗ６は、次のようにして形成されたものである。すなわち、ホスファゼン化合物とバインダのＰＶｄＦとを溶解させたＮＭＰ溶液にアセチレンブラックと酸化アルミニウムを分散させる。得られた分散溶液を正極合剤層Ｗ２の表面に塗布し、乾燥後、プレス処理を施すことで正極板全体の厚さを調整する。 Further, a flame retardant layer W6 containing a flame retardant is formed on the surface of the positive electrode mixture layer W2, that is, on both surfaces of the positive electrode plate. The thickness of the flame retardant layer W6 is set to 20% or less with respect to the thickness of the positive electrode mixture layer W2. The flame retardant layer W6 contains a carbon material having electronic conductivity, and is made porous by blending a pore forming agent (pore forming agent) so as to have lithium ion permeability. As the flame retardant, a phosphazene compound having phosphorus and nitrogen as a basic skeleton is used. In this example, the blending ratio of the flame retardant is set to 1 wt% or more with respect to the positive electrode mixture. Acetylene black is used for the carbon material contained in the flame retardant layer W6. The mass ratio of the carbon material to the flame retardant is set in the range of 1 to 25%. In addition, aluminum oxide is used as the pore forming agent. The mixing ratio of aluminum oxide can be adjusted according to the ratio of the porosity formed in the flame retardant layer W6. This flame retardant layer W6 is formed as follows. That is, acetylene black and aluminum oxide are dispersed in an NMP solution in which a phosphazene compound and a binder PVdF are dissolved. The obtained dispersion solution is applied to the surface of the positive electrode mixture layer W2, dried, and then subjected to press treatment to adjust the thickness of the entire positive electrode plate.
　ホスファゼン化合物は、一般式（ＮＰＲ２）３または（ＮＰＲ２）４で表される環状化合物である。一般式中のＲは、フッ素や塩素等のハロゲン元素または一価の置換基を示している。一価の置換基としては、メトキシ基やエトキシ基等のアルコキシ基、フェノキシ基やメチルフェノキシ基等のアリールオキシ基、メチル基やエチル基等のアルキル基、フェニル基やトリル基等のアリール基、メチルアミノ基等の置換型アミノ基を含むアミノ基、メチルチオ基やエチルチオ基等のアルキルチオ基、および、フェニルチオ基等のアリールチオ基を挙げることができる。置換基の種類により固体または液体となるが、本例では、８０℃以下の温度環境で固体のホスファゼン化合物が用いられている。また、これらのホスファゼン化合物は、それぞれ所定温度で分解するものである。 The phosphazene compound is a cyclic compound represented by the general formula (NPR 2 ) 3 or (NPR 2 ) 4 . R in the general formula represents a halogen element such as fluorine or chlorine or a monovalent substituent. As monovalent substituents, alkoxy groups such as methoxy group and ethoxy group, aryloxy groups such as phenoxy group and methylphenoxy group, alkyl groups such as methyl group and ethyl group, aryl groups such as phenyl group and tolyl group, Examples thereof include an amino group containing a substituted amino group such as a methylamino group, an alkylthio group such as a methylthio group and an ethylthio group, and an arylthio group such as a phenylthio group. Depending on the type of the substituent, it is solid or liquid, but in this example, a solid phosphazene compound is used in a temperature environment of 80 ° C. or lower. Further, these phosphazene compounds are each decomposed at a predetermined temperature.
　一方、負極板は、負極集電体として圧延銅箔（集電体）Ｗ３を有している。圧延銅箔Ｗ３の厚さは、本例では、１０μｍに設定されている。圧延銅箔Ｗ３の両面には、負極合剤が、正極板と同様に実質的に均等かつ均質に塗着され負極合剤層Ｗ４が形成されている。負極合剤には、負極活物質としてリチウムイオンを吸蔵、放出可能な炭素材を含むが含まれている。負極活物質の炭素材には、本例では、非晶質炭素粉末が用いられている。負極合剤には、例えば、非晶質炭素粉末の９０ｗｔ％に対して、バインダとしてＰＶｄＦの１０ｗｔ％が配合されている。圧延銅箔Ｗ３に負極合剤を塗着するときには、分散溶媒のＮＭＰが用いられる。圧延銅箔Ｗ３の長寸方向一側の側縁には、正極板と同様に幅３０ｍｍの負極合剤の未塗着部が形成されており、負極リード片３が形成されている。隣り合う負極リード片３の間隔が２０ｍｍ、負極リード片３の幅が５ｍｍに設定されている。負極板は、乾燥後、プレス加工され、幅８６ｍｍに裁断されている。なお、負極板の長さは、正極板および負極板を捲回したときに、捲回最内周および最外周で捲回方向に正極板が負極板からはみ出すことがないように、正極板の長さより１２０ｍｍ長く設定されている。また、負極合剤層Ｗ４（合剤塗布部）の幅は、捲回方向と垂直方向において正極合剤層Ｗ２が負極合剤層Ｗ４からはみ出すことがないように、正極合剤層Ｗ２の幅より６ｍｍ長く設定されている。 On the other hand, the negative electrode plate has a rolled copper foil (current collector) W3 as a negative electrode current collector. In this example, the thickness of the rolled copper foil W3 is set to 10 μm. On both surfaces of the rolled copper foil W3, the negative electrode mixture is applied substantially uniformly and uniformly in the same manner as the positive electrode plate to form a negative electrode mixture layer W4. The negative electrode mixture contains a carbon material capable of occluding and releasing lithium ions as a negative electrode active material. In this example, amorphous carbon powder is used for the carbon material of the negative electrode active material. In the negative electrode mixture, for example, 10 wt% of PVdF is blended as a binder with respect to 90 wt% of the amorphous carbon powder. When applying the negative electrode mixture to the rolled copper foil W3, NMP as a dispersion solvent is used. An uncoated portion of a negative electrode mixture having a width of 30 mm is formed on the side edge on one side in the longitudinal direction of the rolled copper foil W3, and a negative electrode lead piece 3 is formed. The interval between the adjacent negative electrode lead pieces 3 is set to 20 mm, and the width of the negative electrode lead piece 3 is set to 5 mm. The negative electrode plate is pressed after drying and cut into a width of 86 mm. The length of the negative electrode plate is such that when the positive electrode plate and the negative electrode plate are wound, the positive electrode plate does not protrude from the negative electrode plate in the winding direction at the innermost winding and outermost winding. 120 mm longer than the length. The width of the negative electrode mixture layer W4 (mixture application portion) is such that the positive electrode mixture layer W2 does not protrude from the negative electrode mixture layer W4 in the direction perpendicular to the winding direction. 6 mm longer.
　次に、本実施形態に従い作製したリチウムイオン二次電池２０の実施例について説明する。なお、比較のために作製した比較例および参考例のリチウムイオン二次電池についても併記する。 Next, examples of the lithium ion secondary battery 20 manufactured according to the present embodiment will be described. In addition, it describes together about the lithium ion secondary battery of the comparative example produced for the comparison, and a reference example.
（実施例１）
　実施例１では、難燃化剤のホスファゼン化合物（株式会社ブリヂストン製、商品名ホスライト（登録商標）、固体状、分解温度２５０℃以上）とＰＶｄＦとを溶解させたＮＭＰ溶液に酸化アルミニウムおよび炭素材料のアセチレンブラック（電気化学工業株式会社製、デンカブラックＨＳ１００）を分散させ分散溶液を調製した。このとき、下表１に示すように、炭素材料の難燃化剤に対する質量比を１％の割合に調整した。この分散溶液を正極合剤層Ｗ２の表面に塗布し、分散溶液の塗布量を調整することで、正極合剤に対する難燃化剤の配合割合を１ｗｔ％の割合に調整した。 Example 1
In Example 1, a phosphazene compound as a flame retardant (trade name Phoslite (registered trademark) manufactured by Bridgestone Corporation, solid, decomposition temperature 250 ° C. or higher) and PVdF were dissolved in an NMP solution containing aluminum oxide and a carbon material. Acetylene black (Denka Black HS100, manufactured by Denki Kagaku Kogyo Co., Ltd.) was dispersed to prepare a dispersion solution. At this time, as shown in Table 1 below, the mass ratio of the carbon material to the flame retardant was adjusted to 1%. This dispersion solution was applied to the surface of the positive electrode mixture layer W2, and the application amount of the dispersion solution was adjusted to adjust the blending ratio of the flame retardant to the positive electrode mixture to 1 wt%.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
（実施例２～実施例７）
　表１に示すように、実施例２～実施例７では、炭素材料の難燃化剤に対する質量比を２～２５％の範囲で変えること以外は実施例１と同様にした。すなわち、炭素材料の質量比は、実施例２では２％、実施例３では５％、実施例４では１０％、実施例５では１５％、実施例６では２０％、実施例７では２５％、にそれぞれ調整した。 (Example 2 to Example 7)
As shown in Table 1, Examples 2 to 7 were the same as Example 1 except that the mass ratio of the carbon material to the flame retardant was changed in the range of 2 to 25%. That is, the mass ratio of the carbon material is 2% in Example 2, 5% in Example 3, 10% in Example 4, 15% in Example 5, 20% in Example 6, and 25% in Example 7. , Respectively.
（比較例１～比較例９）
　表１に示すように、比較例１では、難燃化剤層に炭素材料が含まれていないこと以外は
実施例１と同様にした。すなわち、比較例１のリチウムイオン二次電池は、炭素材料の難燃化剤に対する質量比が０％の電池である。比較例２～比較例９では、炭素材料の難燃化剤に対する質量比を３０～１００％の範囲で変える以外は実施例１と同様にした。すなわち、炭素材料の質量比は、比較例２では３０％、比較例３では４０％、比較例４では５０％、比較例５では６０％、比較例６では７０％、比較例７では８０％、比較例８では９０％、比較例９では１００％、にそれぞれ調整した。 (Comparative Examples 1 to 9)
As shown in Table 1, Comparative Example 1 was the same as Example 1 except that the flame retardant layer did not contain a carbon material. That is, the lithium ion secondary battery of Comparative Example 1 is a battery in which the mass ratio of the carbon material to the flame retardant is 0%. Comparative Examples 2 to 9 were the same as Example 1 except that the mass ratio of the carbon material to the flame retardant was changed in the range of 30 to 100%. That is, the mass ratio of the carbon material is 30% in Comparative Example 2, 40% in Comparative Example 3, 50% in Comparative Example 4, 60% in Comparative Example 5, 70% in Comparative Example 6, and 80% in Comparative Example 7. Comparative Example 8 was adjusted to 90%, and Comparative Example 9 was adjusted to 100%.
（試験１）
　実施例及び比較例の各リチウムイオン二次電池について、以下の測定、試験を行った。環境温度２５℃、７００ｍＡ（１Ｃ）で放電容量を測定し、炭素材料の難燃化剤に対する質量比が０％の比較例１のリチウムイオン二次電池の１Ｃにおける放電容量を１００％として、他の実施例及び比較例の各リチウムイオン二次電池について放電容量比を求めた。 (Test 1)
The following measurements and tests were performed on the lithium ion secondary batteries of Examples and Comparative Examples. The discharge capacity was measured at an ambient temperature of 25 ° C. and 700 mA (1C), and the discharge capacity at 1C of the lithium ion secondary battery of Comparative Example 1 in which the mass ratio of the carbon material to the flame retardant was 0% was assumed to be 100%. The discharge capacity ratio was determined for each of the lithium ion secondary batteries of Examples and Comparative Examples.
　図２に示すように、炭素材料の質量比が０％の比較例１の放電容量比と比較すると、炭素材料の質量比が増加する実施例１～実施例７及び比較例２～比較例９の放電容量比は、一旦増加した後に、徐々に低下する特性が見られた。すなわち、炭素材料の質量比が２５％より大きい比較例２～比較例９においては、放電容量比は１００％より小さい値となり、炭素材料の質量比が大きくなると徐々に減少した。これらに対して、炭素材料の質量比が１％～２５％の範囲の実施例１～実施例７の電池において、放電容量比は、いずれも１００％を超える１０２％以上であった。また、炭素材料の質量比が２％～２０％の範囲の実施例２～実施例６の電池において、放電容量比は１０７％以上となり、より大きな値を示した。更に、炭素材料の質量比が５％の実施例３のリチウムイオン二次電池において、放電容量比は１３３％となり最大値を示した。これにより、電子伝導性を有し、質量比が２５％以下の炭素材料が難燃化剤層に含まれると、放電特性の低下を抑制することができることが判明した。また、炭素材料の質量比が２５％より大きくなると、難燃化剤層の厚さが相対的に大きくなることで、容量や出力が低下したため、放電容量比が低下したと考えられる。 As shown in FIG. 2, Examples 1 to 7 and Comparative Examples 2 to 9 increase the mass ratio of the carbon material as compared with the discharge capacity ratio of Comparative Example 1 where the mass ratio of the carbon material is 0%. The discharge capacity ratio increased once and then gradually decreased. That is, in Comparative Examples 2 to 9 where the mass ratio of the carbon material was greater than 25%, the discharge capacity ratio was a value smaller than 100%, and gradually decreased as the mass ratio of the carbon material increased. On the other hand, in the batteries of Examples 1 to 7 in which the mass ratio of the carbon material was in the range of 1% to 25%, the discharge capacity ratio was 102% or more exceeding 100%. Further, in the batteries of Examples 2 to 6 in which the mass ratio of the carbon material was in the range of 2% to 20%, the discharge capacity ratio was 107% or more, indicating a larger value. Furthermore, in the lithium ion secondary battery of Example 3 in which the mass ratio of the carbon material was 5%, the discharge capacity ratio was 133%, indicating the maximum value. Accordingly, it has been found that when a carbon material having electronic conductivity and a mass ratio of 25% or less is included in the flame retardant layer, it is possible to suppress a decrease in discharge characteristics. In addition, when the mass ratio of the carbon material is greater than 25%, the thickness of the flame retardant layer is relatively increased, and thus the capacity and output are decreased. Therefore, it is considered that the discharge capacity ratio is decreased.
（試験２）
　各実験例および比較例のリチウムイオン二次電池について、過充電試験を行い、安全性を評価した。過充電試験では、電池中央部に熱電対を配置し、各リチウムイオン二次電池を０．５Ｃの電流値で充電し続けたときの電池表面の温度を測定した。過充電試験における電池表面の温度を下表２に示す。 (Test 2)
About the lithium ion secondary battery of each experiment example and a comparative example, the overcharge test was done and safety | security was evaluated. In the overcharge test, a thermocouple was placed in the center of the battery, and the temperature of the battery surface when each lithium ion secondary battery was continuously charged at a current value of 0.5 C was measured. Table 2 shows the temperature of the battery surface in the overcharge test.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２に示すように、難燃化剤層に炭素材料が含まれていない比較例１では、表面温度は１２１．４℃を示した。難燃化剤層に炭素材料が含まれている実施例１～実施例７及び比較例２～比較例９では、比較例１との温度差は僅かであった。従って、難燃化剤層に炭素材料が含まれることによる電池の表面温度の上昇は、電池の安全性を確保できる範囲内であると判断できる。 As shown in Table 2, in Comparative Example 1 in which the flame retardant layer did not contain a carbon material, the surface temperature was 121.4 ° C. In Examples 1 to 7 and Comparative Examples 2 to 9 in which the flame retardant layer contains a carbon material, the temperature difference from Comparative Example 1 was slight. Therefore, it can be determined that the increase in the surface temperature of the battery due to the carbon material contained in the flame retardant layer is within a range in which the safety of the battery can be ensured.
（参考例１～参考例９）
　参考例１～参考例９では、難燃化剤の効果を評価することを目的としており、いずれも難燃化剤層Ｗ６に炭素材料が含まれていないことと、正極合剤に対する難燃化剤の配合割合を変えたこと以外は実施例１と同様にした。下表３に示すように、難燃化剤の配合割合は、参考例１では１ｗｔ％、参考例２では２ｗｔ％、参考例３では３ｗｔ％、参考例４では５ｗｔ％、参考例５では６ｗｔ％、参考例６では８ｗｔ％、参考例７では１０ｗｔ％、参考例８では１５ｗｔ％、参考例９では２０ｗｔ％、にそれぞれ調整した。 (Reference Example 1 to Reference Example 9)
Reference Examples 1 to 9 are intended to evaluate the effect of the flame retardant, and all of them contain no carbon material in the flame retardant layer W6, and are flame retardant for the positive electrode mixture. The procedure was the same as Example 1 except that the blending ratio of the agent was changed. As shown in Table 3 below, the blending ratio of the flame retardant is 1 wt% in Reference Example 1, 2 wt% in Reference Example 2, 3 wt% in Reference Example 3, 5 wt% in Reference Example 4, and 6 wt in Reference Example 5. %, Reference Example 6 was adjusted to 8 wt%, Reference Example 7 was adjusted to 10 wt%, Reference Example 8 was adjusted to 15 wt%, and Reference Example 9 was adjusted to 20 wt%.
（参考例１０）
　表３に示すように、参考例１０では、正極合剤層Ｗ２の表面に難燃化剤層Ｗ６を形成しないこと以外は実施例１と同様にした。すなわち、参考例１０のリチウムイオン二次電池は従来の電池である。 (Reference Example 10)
As shown in Table 3, in Reference Example 10, the same procedure as in Example 1 was performed except that the flame retardant layer W6 was not formed on the surface of the positive electrode mixture layer W2. That is, the lithium ion secondary battery of Reference Example 10 is a conventional battery.
（試験）
　各参考例のリチウムイオン二次電池について、過充電試験を行い、安全性を評価した。過充電試験では、電池中央部に熱電対を配置し、各リチウムイオン二次電池を０．５Ｃの電流値で充電し続けたときの電池表面の温度を測定した。過充電試験における電池表面最高温度を下表４に示す。 (test)
About the lithium ion secondary battery of each reference example, the overcharge test was done and safety | security was evaluated. In the overcharge test, a thermocouple was placed in the center of the battery, and the temperature of the battery surface when each lithium ion secondary battery was continuously charged at a current value of 0.5 C was measured. Table 4 shows the maximum battery surface temperature in the overcharge test.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　表４に示すように、難燃化剤層Ｗ６が形成されていない参考例１０のリチウムイオン二次電池では、過充電試験により電池表面最高温度が４８２．９℃に達した。これに対して、難燃化剤層Ｗ６に難燃化剤が含有された参考例１～参考例９のリチウムイオン二次電池２０では、いずれも電池表面最高温度が低下しており、難燃化剤の配合割合を大きくすることで電池表面最高温度の低下する割合も大きくなることが判った。難燃化剤が正極合剤に対して１ｗｔ％配合されていれば（参考例１）、参考例１０のリチウムイオン二次電池と比べて電池表面最高温度を低下させることができる。活物質の熱分解反応やその連鎖反応を抑制することを考慮すれば、電池表面最高温度がおよそ１５０℃以下に抑えられることが好ましい。このことは、難燃化剤の配合割合を１０ｗｔ％以上とすることで達成することができる（参考例７～参考例９）。 As shown in Table 4, in the lithium ion secondary battery of Reference Example 10 in which the flame retardant layer W6 was not formed, the battery surface maximum temperature reached 482.9 ° C. by the overcharge test. On the other hand, in each of the lithium ion secondary batteries 20 of Reference Examples 1 to 9 in which the flame retardant contained in the flame retardant layer W6, the maximum battery surface temperature is lowered, and the flame retardant is reduced. It has been found that increasing the blending ratio of the agent also increases the rate at which the battery surface maximum temperature decreases. When the flame retardant is blended in an amount of 1 wt% with respect to the positive electrode mixture (Reference Example 1), the battery surface maximum temperature can be lowered as compared with the lithium ion secondary battery of Reference Example 10. In consideration of suppressing the thermal decomposition reaction and the chain reaction of the active material, it is preferable that the maximum battery surface temperature is suppressed to about 150 ° C. or less. This can be achieved by setting the blending ratio of the flame retardant to 10 wt% or more (Reference Examples 7 to 9).
（作用等）
　次に、本実施形態のリチウムイオン二次電池２０の作用等について説明する。 (Action etc.)
Next, the operation and the like of the lithium ion secondary battery 20 of the present embodiment will be described.
　本実施形態では、電極群６を構成する正極板の正極合剤層Ｗ２の表面に、難燃化剤としてホスファゼン化合物が含有された難燃化剤層Ｗ６が形成されている。このホスファゼン化合物は、電池異常時等の高温環境下の所定温度で分解する。難燃化剤層Ｗ６が正極合剤層Ｗ２の表面に形成されることで、ホスファゼン化合物が正極活物質の近傍に存在することとなる。このため、リチウムイオン二次電池２０が異常な高温環境下に曝されたときや電池異常が生じたときに、正極活物質の熱分解反応やその連鎖反応で電池温度が上昇すると、ホスファゼン化合物が分解する。これにより、電池構成材料の燃焼が抑制されるため、リチウムイオン二次電池２０の電池挙動を穏やかにし安全性を確保することができる。 In this embodiment, a flame retardant layer W6 containing a phosphazene compound as a flame retardant is formed on the surface of the positive electrode mixture layer W2 of the positive electrode plate constituting the electrode group 6. This phosphazene compound decomposes at a predetermined temperature in a high temperature environment such as when the battery is abnormal. By forming the flame retardant layer W6 on the surface of the positive electrode mixture layer W2, the phosphazene compound is present in the vicinity of the positive electrode active material. For this reason, when the lithium ion secondary battery 20 is exposed to an abnormally high temperature environment or when a battery abnormality occurs, if the battery temperature rises due to the thermal decomposition reaction or chain reaction of the positive electrode active material, the phosphazene compound becomes Decompose. Thereby, since combustion of a battery constituent material is suppressed, the battery behavior of the lithium ion secondary battery 20 can be moderated and safety can be ensured.
　また、本実施形態では、電子伝導性を有し、難燃化剤に対する質量比が２５％以下のアセチレンブラックが、難燃化剤層Ｗ６に含有されている。このため、正極合剤層Ｗ２の表面に難燃化剤層Ｗ６が形成されていても、充放電特性の低下を抑制することができる。また、難燃化剤層Ｗ６に多孔が形成され多孔化されている。このため、通常の電池使用（充放電）時にはリチウムイオンが正負極板間を十分に移動することができ、電池性能を確保することができる。更に、難燃化剤層Ｗ６が正極合剤層Ｗ２の表面に形成されているため、正極合剤層Ｗ２では、電極反応を生じさせる正極活物質の配合割合が確保されるので、リチウムイオン二次電池２０の容量や出力を確保することができる。 In this embodiment, acetylene black having electronic conductivity and having a mass ratio with respect to the flame retardant of 25% or less is contained in the flame retardant layer W6. For this reason, even if the flame retardant layer W6 is formed on the surface of the positive electrode mixture layer W2, it is possible to suppress a decrease in charge / discharge characteristics. In addition, the flame retardant layer W6 has a porous structure. For this reason, during normal battery use (charging / discharging), lithium ions can sufficiently move between the positive and negative electrode plates, and battery performance can be ensured. Furthermore, since the flame retardant layer W6 is formed on the surface of the positive electrode mixture layer W2, the positive electrode mixture layer W2 ensures a blending ratio of the positive electrode active material that causes an electrode reaction. The capacity and output of the secondary battery 20 can be ensured.
　更に、本実施形態では、難燃化剤層Ｗ６の厚さは、正極合剤層Ｗ２の厚さに対して、２０％以下に設定されている。このため、正極合剤層Ｗ２の表面に難燃化剤層Ｗ６が形成されていても、電池の充放電時にリチウムイオンの正負極板間の移動が妨げられない程度の厚さに設定されているため、リチウムイオン二次電池２０の充放電性能を確保することができる。 Furthermore, in this embodiment, the thickness of the flame retardant layer W6 is set to 20% or less with respect to the thickness of the positive electrode mixture layer W2. For this reason, even if the flame retardant layer W6 is formed on the surface of the positive electrode mixture layer W2, the thickness is set so as not to prevent the movement of lithium ions between the positive and negative electrode plates during charging and discharging of the battery. Therefore, the charge / discharge performance of the lithium ion secondary battery 20 can be ensured.
　なお、本実施形態では、正極合剤層Ｗ２の表面、すなわち、正極板の両面に難燃化剤層Ｗ６を形成する例を示したが、本発明はこれに限定されるものではない。例えば、難燃化剤層Ｗ６を負極板やセパレータＷ５に形成するようにしてもよい。また、難燃化剤層Ｗ６が、正極板、負極板およびセパレータＷ５の少なくとも１つの片面のみに形成されていてもよい。更に、本実施形態では、バインダとしてＰＶｄＦを用いて難燃化剤層Ｗ６を形成させる例を示したが、本発明はこれに限定されるものではなく、難燃化剤層Ｗ６を形成可能であればいかなるバインダを用いてもよい。 In the present embodiment, an example in which the flame retardant layer W6 is formed on the surface of the positive electrode mixture layer W2, that is, both surfaces of the positive electrode plate is shown, but the present invention is not limited to this. For example, the flame retardant layer W6 may be formed on the negative electrode plate or the separator W5. Moreover, the flame retardant layer W6 may be formed only on at least one side of the positive electrode plate, the negative electrode plate, and the separator W5. Furthermore, in this embodiment, although the example which forms the flame retardant layer W6 using PVdF as a binder was shown, this invention is not limited to this, The flame retardant layer W6 can be formed. Any binder can be used.
　また、本実施形態では、難燃化剤層Ｗ６の形成時に、造孔剤として酸化アルミニウムを配合する例を示したが、本発明はこれに限定されるものではない。通常の充放電時にリチウムイオンが通過可能なように難燃化剤層Ｗ６が多孔化されていればよく、用いる造孔剤にも制限されるものではなく、造孔剤を用いなくてもよい。 Moreover, in this embodiment, the example which mix | blends an aluminum oxide as a pore making material was shown at the time of formation of the flame retardant layer W6, However, This invention is not limited to this. The flame retardant layer W6 only needs to be porous so that lithium ions can pass during normal charge and discharge, and is not limited to the pore forming agent used, and the pore forming agent may not be used. .
　更に、本実施形態では、難燃化剤層Ｗ６に配合する難燃化剤の割合を１ｗｔ％以上に設定する例を示した（参考例１～参考例９）。難燃化剤の配合割合が１ｗｔ％に満たないと熱分解反応による温度上昇を抑制することが難しくなり、反対に、２０ｗｔ％を超えると難燃化剤層Ｗ６の厚みが相対的に大きくなり、容量や出力を低下させることとなる。このため、難燃化剤の配合割合を１～２０ｗｔ％の範囲とすることが好ましい。また、熱分解反応の連鎖反応による更なる温度上昇を抑制することを考慮すれば、難燃化剤の配合割合を１０ｗｔ％以上とすることがより好ましい。 Furthermore, in this embodiment, the example which sets the ratio of the flame retardant mix | blended with the flame retardant layer W6 to 1 wt% or more was shown (reference example 1 to reference example 9). If the blending ratio of the flame retardant is less than 1 wt%, it is difficult to suppress the temperature rise due to the thermal decomposition reaction. Conversely, if it exceeds 20 wt%, the thickness of the flame retardant layer W6 becomes relatively large. The capacity and output will be reduced. For this reason, the blending ratio of the flame retardant is preferably in the range of 1 to 20 wt%. In consideration of suppressing further temperature increase due to the chain reaction of the thermal decomposition reaction, the blending ratio of the flame retardant is more preferably 10 wt% or more.
　また更に、本実施形態では、炭素材料の難燃化剤に対する質量比を１～２５％の範囲に設定する例を示した（実施例１～実施例７）。炭素材料の質量比が１％に満たないと、正極合剤層Ｗ２の表面に難燃化剤層Ｗ６が形成されていることから、充放電特性が低下しやすくなり、反対に、２５％を超えると難燃化剤層Ｗ６の厚さが相対的に大きくなり、充放電特性は低下することとなる。また、本実施形態では、炭素材料の質量比が２～２０％の範囲のとき、より充放電特性が向上した（実施例２～実施例６）。このため、炭素材料の質量比は２～２０％の範囲とすることがより好ましい。 Furthermore, in the present embodiment, an example is shown in which the mass ratio of the carbon material to the flame retardant is set in the range of 1 to 25% (Example 1 to Example 7). If the mass ratio of the carbon material is less than 1%, since the flame retardant layer W6 is formed on the surface of the positive electrode mixture layer W2, the charge / discharge characteristics are liable to deteriorate, and conversely, 25% If it exceeds, the thickness of the flame retardant layer W6 becomes relatively large, and the charge / discharge characteristics are deteriorated. In the present embodiment, when the mass ratio of the carbon material is in the range of 2 to 20%, the charge / discharge characteristics are further improved (Examples 2 to 6). For this reason, the mass ratio of the carbon material is more preferably in the range of 2 to 20%.
　更にまた、本実施形態では、難燃化剤としてホスファゼン化合物を例示したが、本発明はこれに限定されるものではなく、所定温度で分解し活物質の熱分解反応やその連鎖反応による温度上昇を抑制することができるものであればよい。また、ホスファゼン化合物についても本実施形態で例示した化合物以外の化合物を用いることも可能である。 Furthermore, in the present embodiment, the phosphazene compound is exemplified as the flame retardant, but the present invention is not limited to this, and the temperature is increased by decomposition at a predetermined temperature and thermal decomposition reaction of the active material or its chain reaction. What is necessary is just to be able to suppress this. Moreover, it is also possible to use compounds other than the compound illustrated by this embodiment also about a phosphazene compound.
　また、本実施形態では、難燃化剤層Ｗ６に含まれる炭素材料にアセチレンブラックを例示したが、本発明はこれに限定されるものではなく、グラファイト、カーボンブラック、カーボンナノチューブ、ガラス状炭素から選択される１種または少なくとも２種の組み合わせであればよい。炭素材料にグラファイトを使用した場合、グラファイトは、鱗片状グラファイト、人造グラファイト、土状グラファイトから選択される１種または少なくとも２種の組み合わせを使用することができる。 In the present embodiment, acetylene black is exemplified as the carbon material included in the flame retardant layer W6. However, the present invention is not limited to this, and graphite, carbon black, carbon nanotube, and glassy carbon are used. One type or a combination of at least two types may be selected. When graphite is used as the carbon material, the graphite may be one or a combination of at least two selected from scale-like graphite, artificial graphite, and earth-like graphite.
　更に、本実施形態では、ハイブリッド自動車に搭載される円柱型リチウムイオン二次電池２０を例示したが、本発明はこれに限定されるものではなく、電池容量が約３Ａｈを超える大型のリチウムイオン二次電池に適用することができる。また、本実施形態では、正極板、負極板を捲回した電極群６を例示したが、本発明はこれに限定されるものではなく、例えば、矩形状の正極板、負極板を積層した電極群としてもよい。更に、電池形状についても、円柱型以外に角型等としてもよいことはもちろんである。 Furthermore, in the present embodiment, the cylindrical lithium ion secondary battery 20 mounted on a hybrid vehicle is illustrated, but the present invention is not limited to this, and a large-sized lithium ion secondary battery having a battery capacity exceeding about 3 Ah. It can be applied to the next battery. Moreover, in this embodiment, although the electrode group 6 which wound the positive electrode plate and the negative electrode plate was illustrated, this invention is not limited to this, For example, the electrode which laminated | stacked the rectangular positive electrode plate and the negative electrode plate It is good also as a group. Furthermore, the battery shape may be a square shape in addition to the cylindrical shape.
　また更に、本実施形態では、正極活物質に、層状結晶構造を有するマンガンニッケルコバルト複酸リチウム粉末、スピネル結晶構造を有するマンガン酸リチウム粉末のいずれかのリチウム遷移金属複酸化物を用いる例を示したが、本発明で用いることのできる正極活物質としてはリチウム遷移金属複酸化物であればよい。負極活物質の種類、非水電解液の組成等についても特に制限されるものではない。また、本発明はリチウムイオン二次電池に制限されるものではなく、非水電解液を用いた非水電解液電池に適用できることはいうまでもない。 Furthermore, in the present embodiment, an example in which a lithium transition metal double oxide of either a manganese nickel cobalt double acid powder having a layered crystal structure or a lithium manganate powder having a spinel crystal structure is used as the positive electrode active material is shown. However, the positive electrode active material that can be used in the present invention may be any lithium transition metal double oxide. The type of the negative electrode active material, the composition of the nonaqueous electrolytic solution, and the like are not particularly limited. Further, the present invention is not limited to the lithium ion secondary battery, and it goes without saying that the present invention can be applied to a nonaqueous electrolyte battery using a nonaqueous electrolyte.
　本発明は電池異常時の安全性を確保し電池使用時の充放電特性の低下を抑制することができる非水電解液電池を提供するため、非水電解液電池の製造、販売に寄与するので、産業上の利用可能性を有する。 Since the present invention provides a non-aqueous electrolyte battery that can ensure safety in the event of battery abnormalities and suppress deterioration of charge / discharge characteristics when the battery is used, it contributes to the manufacture and sale of non-aqueous electrolyte batteries. Have industrial applicability.

Claims (6)

  1. 　活物質を含む正極合剤層が集電体に形成された正極板と、活物質を含む負極合剤層が集電体に形成された負極板とが多孔質セパレータを介して配置された非水電解液電池において、前記正極板、負極板およびセパレータの少なくとも１種の片面または両面に、難燃化剤を含む難燃化剤層が配され、電子伝導性を有し、該難燃化剤に対する質量比が２５％以下の炭素材料が前記難燃化剤層に含まれたことを特徴とする非水電解液電池。 A positive electrode plate in which a positive electrode mixture layer containing an active material is formed on a current collector and a negative electrode plate in which a negative electrode mixture layer containing an active material is formed on a current collector are arranged via a porous separator. In the water electrolyte battery, a flame retardant layer containing a flame retardant is disposed on one or both surfaces of the positive electrode plate, the negative electrode plate, and the separator, and has an electronic conductivity. A non-aqueous electrolyte battery characterized in that a carbon material having a mass ratio to the agent of 25% or less is contained in the flame retardant layer.
  2. 　前記難燃化剤層に含まれる炭素材料は、前記難燃化剤に対する質量比が１％以上であることを特徴とする請求項１に記載の非水電解液電池。 The non-aqueous electrolyte battery according to claim 1, wherein the carbon material contained in the flame retardant layer has a mass ratio of 1% or more to the flame retardant.
  3. 　前記難燃化剤層に含まれる炭素材料は、前記難燃化剤に対する質量比が２％～２０％の範囲であることを特徴とする請求項２に記載の非水電解液電池。 The non-aqueous electrolyte battery according to claim 2, wherein the carbon material contained in the flame retardant layer has a mass ratio of 2% to 20% with respect to the flame retardant.
  4. 　前記難燃化剤層は、前記正極板ないし前記負極板の片面または両面に配されており、前記難燃化剤層の厚さは、前記正極合剤層または前記負極合剤層の厚さに対して、２０％以下であることを特徴とする請求項３に記載の非水電解液電池。 The flame retardant layer is disposed on one or both sides of the positive electrode plate or the negative electrode plate, and the thickness of the flame retardant layer is the thickness of the positive electrode mixture layer or the negative electrode mixture layer. The nonaqueous electrolyte battery according to claim 3, wherein the nonaqueous electrolyte battery is 20% or less.
  5. 　前記難燃化剤層に含まれる炭素材料は、グラファイト、カーボンブラック、アセチレンブラック、カーボンナノチューブ、ガラス状炭素から選択される１種または少なくとも２種の組み合わせあることを特徴とする請求項１に記載の非水電解液電池。 The carbon material contained in the flame retardant layer is one or a combination of at least two selected from graphite, carbon black, acetylene black, carbon nanotubes, and glassy carbon. Non-aqueous electrolyte battery.
  6. 　前記グラファイトは、鱗片状グラファイト、人造グラファイト、土状グラファイトから選択される１種または少なくとも２種の組み合わせであることを特徴とする請求項５に記載の非水電解液電池。 6. The non-aqueous electrolyte battery according to claim 5, wherein the graphite is one or a combination of at least two selected from flaky graphite, artificial graphite, and earth-like graphite.
PCT/JP2011/070144 2010-09-06 2011-09-05 Nonaqueous electrolyte battery WO2012033045A1 (en)

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